“Hardball” host Chris Matthews suggested on Friday that John McCain grilled defense secretary nominee Chuck Hagel during his confirmation hearing because of pent-up resentment over the Vietnam War, adding that he is “absolutely convinced” the Arizona senator and former prisoner of war suffered a traumatic flashback.

“Let me start tonight with this — why is John McCain so angry?” Matthews said. “Forty years after the Vietnam POWs came home, the most famous of them is angrier than ever. Why is America — why are we fighting the Vietnam War all over again in the United States Senate? The ticked-off vitriol against Chuck Hagel, what is it about? Is it for show? Is it about something Hagel said in the cloakroom?”

“Is it about the basic unfairness of Vietnam itself, that some went and some didn’t?” he continued. “Is it about Lyndon Johnson’s inability to either win that war or end it? What is it that burns so deeply in John McCain these days?”

Matthews also floated the possibility that McCain was upset about his 2000 Republican primary loss to George W. Bush. But he went on to tell his guests, Mother Jones magazine’s David Corn and The Grio’s Joy Reid, that psychological factors were at play.

“Well, tonight, we dig into the deep well of resentment burning in John McCain’s patriotic heart — a resentment not against the North Vietnamese who imprisoned and tortured him all those years, not against George W. Bush and his political henchmen who tried to stain McCain’s reputation back in 2000 — but against a guy who fought against fear and rallied against wounds, just like he did in the same army of America’s long nightmare in Vietnam, Chuck Hagel. A nightmare, by the way, whose flashbacks must haunt still the mind and heart of John Sidney McCain. … I’m absolutely convinced we’re watching a flashback.”